PALAEONTOLOGY OF NEW YORK. 
318 
Nucula bellistriata. 
PLATE XLVI, FIGS. 1-9. 
Nuculites beliastriata, Conrad. Geol. Surv. N. Y., Ann. Rep., p. 40. 1841. 
Nucula beliastriata (Conrad), Hall. Prelim. Notice Lamellibranchiata, 2, p. 2. 1870. 
“ “ “ “ Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 46, figs. 
1-11. 1883. 
Shell of medium size, broadly ovate, usually somewhat wider behind ; length 
about one-fourth greater than the height; basal margin regularly curving. 
Posterior end broad and rounded. Cardinal line oblique and arcuate. Ante¬ 
rior end short, declining rapidly from the beaks, and abruptly rounded below. 
Valves convex, gibbous on the umbo. 
Beaks, at about the anterior fourth, appressed, rising above the liinge-line, 
directed forward. Umbonal slope rounded, extending from the beaks in an 
arching direction, to above the post-basal extremity. 
Surface marked by fine, regular, sharp, concentric strite, which do not 
appear to be aggregated into fascicles, but are sometimes interrupted, and the 
surface undulated by strong varices of growth. 
The cast of the interior shows the strong muscular impressions and a 
broad, thickened hinge. 
Three specimens measure respectively 21, 17 and 16 mm. in length, and 
14, 13 and 12.5 mm. in height. 
The distinguishing characters of this species are its broad and sub-circular 
form and regular concentric strias. In some of its phases it resembles N. vari¬ 
cose/., but that species is sub-trigonal in outline, with larger incurved beaks, and 
the striae are fasciculate, forming strong undulations of the surface at irregular 
intervals. It is less gibbous and broader than N. Randalli, the striae are finer, 
usually without varices of growth, and the beaks more appressed and directed 
forward. 
Formation and localities. In the shales of the Hamilton group, in Schoharie 
county; near Smnyra, Chenango county; at numerous localities in Onondaga 
county, and on the shores of Seneca, Cayuga and Canandaigua lakes, N. Y. 
